Countr (version 3.6.1)

surv: Wrapper to built-in survival functions

Description

Wrapper to built-in survival functions

Usage

surv(t, distPars, dist)

Value

a double, giving the value of the survival function at time point t at the parameters' values.

Arguments

t

double, time point where the survival is to be evaluated at.

distPars

Rcpp::List with distribution specific slots, see section ‘Details’.

dist

character name of the built-in distribution, see section ‘Details’.

Details

The function wraps all builtin-survival distributions. User can choose between the weibull, gamma, gengamma(generalized gamma) and burr (Burr type XII distribution). It is the user responsibility to pass the appropriate list of parameters as follows:

weibull

scale (the scale) and shape (the shape) parameters.

burr

scale (the scale) and shape1 (the shape1) and shape2 (the shape2) parameters.

gamma

scale (the scale) and shape (the shape) parameter.

gengamma

mu (location), sigma (scale) and Q (shape) parameters.

Examples

tt <- 2.5
## weibull

distP <- list(scale = 1.2, shape = 1.16)
alpha <- exp(-log(distP[["scale"]]) / distP[["shape"]])
pweibull(q = tt, scale = alpha, shape = distP[["shape"]],
                      lower.tail = FALSE)
surv(tt, distP, "weibull") ## (almost) same

## gamma
distP <- list(shape = 0.5, rate = 1.0 / 0.7)
pgamma(q = tt, rate = distP[["rate"]], shape = distP[["shape"]],
                    lower.tail = FALSE)
surv(tt, distP, "gamma")  ## (almost) same

## generalized gamma
distP <- list(mu = 0.5, sigma = 0.7, Q = 0.7)
flexsurv::pgengamma(q = tt, mu = distP[["mu"]],
                    sigma = distP[["sigma"]],
                    Q = distP[["Q"]],
                    lower.tail = FALSE)
surv(tt, distP, "gengamma")  ## (almost) same